1 82 O'Brien . — The Proteids of Wheat. 
him to the conclusion that gluten is formed by the action of 
a ferment on the myosin which he had already described as 
the chief proteid of wheat. This theory is based on the 
observations that flour extracted with salt-solution (NaCl) 
yielded no gluten, and that flour kept for some time at 
a temperature of 6o°C. likewise lost its gluten-forming power. 
At the same time the authors admit that no ferment can 
be isolated, and that the addition of fresh flour to that injured 
by heating to 6o°C. does not improve the yield of gluten, as 
should be the case were it dependent only on the presence of 
a ferment. Moreover they themselves suggest that coagulation 
of the myosin, not the destruction of a ferment, may be the 
cause of the non-formation of gluten after the heating of flour. 
Johanssen 38 , treating of gluten in 1888, proposes to himself 
the following questions : (1) How does gluten form in the 
washing operation ? (2) What tissues of the grain take part ? 
In reply to the former he states that he finds the ferment 
theory unnecessary, and seems to imply that gluten occurs as 
such in a finely divided state among the other remains of the 
inner endosperm*cells. The answer to the second emphasises 
what Schenk (III. 6 ) from another point of view had stated in 
1872, that the so-called 4 Kleberzellen ’ contain only aleuron- 
grains and not the gluten ( Kleber ) itself. Johanssen finds 
(1) that a temperature of 6o°C. does not injure the gluten- 
forming power of flour ; (2) that an artificial flour formed by 
mixing powdered gluten and starch behaves in every way 
like ordinary flour. Hence it is probable that gluten exists 
as such in flour. The retarding effect of cold and of salt- 
solutions is ascribed to the less perfect moistening of the 
gluten-particles, the favourable effect of heat to the greater 
cohesiveness of the particles, while its inhibitory effect at 
a high temperature is due to coagulation. 
Kjeldahl’s 37 results I can only state as quoted by Johanssen. 
A minimum and a maximum temperature may be determined, 
limits beyond which no gluten-formation occurs ; 40°C. is the 
optimum. There is a close correspondence between these 
temperatures and the minimum, optimum and maximum for 
